| 摘要 |
PURPOSE:To obtain a fast, small-sized optical A-D converter which has high productivity by applying a magnetic field which is modulated with an analog signal to different-length areas of plural waveguides which have magneto-optical effect. CONSTITUTION:The different-length areas of the magnetic thin film waveguides 3-5 which extend in parallel to one another are applied with the magnetic field which is modulated with the analog signal by electrodes 7 and 8 for magnetic field application which are provided on a buffer layer 6. Therefore, the waveguides 3-5 are applied with a constant magnetic field Hl by an initial magnetic field applying means previously at perpendicular angle to the modulated magnetic field, so the magnetism of the magnetic thin film 2 rotates in proportion to the modulated magnetic field to cause mode conversion corresponding to the angle of rotation, so that the TE mode is converted into the TM mode. Then a mode selection part passes only the TE or TM mode through a comparator with a proper threshold value to perform conversion into a digital signal. Consequently, the fast, small-sized optical A/D converter of simple constitution which has the high productivity and is short in element length is obtained. |
